The mythical city of Camelot, in a time before history began, is a fantastical realm of legendary beasts and mysterious peoples. In this dangerous world, magic has been banned by the ruthless tyrant; Uther Pendragon. Merlin, a young man gifted with extraordinary magical powers, arrives at the gates of Camelot, sent by his mother to start a new life. Though bright-eyed with wonder, the young sorcerer quickly makes enemies, including the heir to Uther's crown, the headstrong Prince Arthur.

The second series of Merlin finds Camelot more vulnerable than ever to the dark forces of magic, forcing Merlin to make difficult decisions in order to protect Arthur, ensure the future king's survival and prevent the mythic kingdom from being destroyed.

Swords, sorcery and swashbuckling adventure return in the third series of Merlin, following our heroes as they face their greatest challenge yet. When misbegotten secrets are exposed and old friends choose new sides, they soon discover that the great battle for Camelot is only just beginning...